This application will establish in Los Angeles County a HIV Prevention Trials Consortium (HPTC) that will be a unit under and will work in close collaboration with the NIH HIV Prevention Trials Network (HPTN). The Los Angeles HPTC will bring to the HPTN a strong local partnership between the following four groups: 1) community advocates and educators who can build support for prevention research in historically underserved communities 2) community-based researchers and epidemiologists with experience working with high-risk populations 3) behavioral scientists and clinicians capable of designing and rapidly implementing Phase I, II and III behavioral and therapeutic prevention and microbicide trials, and, 4) basic virologists and immunologists committed to identifying and measuring the key correlates of protective immunity against HIV. The Los Angeles HPTC has been formed by bringing together community stakeholders and advocates, researchers from four academic institutions (University of Southern California, University of California at Los Angeles, California State University, Long Beach and the Charles R. Drew University of Medicine and Sciences), community-based care and prevention groups serving the African American and Latino, and gay and bisexual communities of Los Angeles (To Help Everyone (T.H.E.) Clinic, AltaMed, and the Gay and Lesbian Center) and experts in HIV epidemiology and prevention research. The goal of this consortium is to make significant contributions to advancing the understanding of effective behavioral, microbicidal and therapeutic interventions that will reduce HIV transmission while building community support for prevention research.